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Cerium oxide nanoparticles or nanoceria of average crystallite size ~ 6, 9 and 14 nm were synthesized by chemical co-precipitation method using deoxyribonucleic acid (DNA) as capping agent. Size dependent structural, optical and magnetic properties of prepared samples were investigated by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), UV-Visible diffuse reflectance spectroscopy and vibrating sample magnetometer (VSM) measurements. The increase in the value of optical band gap with decrease in particle size may be attributed to the quantum confinement effect. The saturation magnetization, coercivity and remanence increases as the particle size decreases from 14 nm to 9 nm. This is in view of the fact that increase in oxygen vacancies may produce magnetic moment by polarizing spins of f electrons of cerium ions located around them. The magnetic properties decreases below a critical size, since thermal energy can overcome the anisotropy and spontaneously reverse the magnetization of a particle from one easy direction to the other. The semiconducting properties along with room temperature ferromagnetism make DNA assisted synthesized nanoceria suitable for fabrication of next generation spintronic devices. [ABSTRACT FROM AUTHOR]

Owing to the unique optical properties, core-shell nanoparticles are receiving increasing attention from the scientific community and have widespread applications in high-resolution optical imaging, enhanced light absorption in photovoltaic and photocatalysis etc. The present research work reports the synthesis of Au-Ag core-shell nanoparticles based nanocomposites with polyvinyl alcohol (PVA) as the host matrix. Morphological analysis of the prepared nanocomposites was carried out using high resolution transmission electron microscopy (HRTEM). Further UV-visible absorption spectroscopy was utilized to study the optical properties such as absorption coefficient (α), optical energy gap (Eg) and Urbach’s energy (Eu) of thus synthesized Au-Ag core-shell PVA nanocomposite. [ABSTRACT FROM AUTHOR]

The peculiar ternary full Heusler alloy Sr2CoSn nanoparticles are synthesized by co-precipitation method. X- ray diffraction pattern confirms the formation of XA or Xα structure of Sr2CoSn. Using Williamson–Hall plot (W–H plot), we are able to use the uniform deformation model and get low value of strain induced broadening. UV-Visible absorption spectrum shows sharp absorption peak at 210 nm and the estimated band gap energy of Sr2CoSn Heusler alloy nanoparticles is Eg = 4.6 eV (from Tauc plot). The presence of Sr2CoSn with the particle size of approximately 90 nm was observed using high resolution scanning electron microscopy. The magnetization measurements were carried out using VSM and studied M verses H hysteresis studies. [ABSTRACT FROM AUTHOR]